Read Yelp's full letter to the FTC accusing Google of violating its deal with the government

Yelp escalated its battle with Google this week with a letter to the US Federal Trade Commission claiming that Google was breaking the terms of a settlement by using images from Yelp in search results.

In 2012, Google brought its FTC investigations to a close by agreeing to allow rival sites to opt-out of allowing Google to "scrape," or collect information or images from websites to use in its own search results.

But in a letter to FTC Chair Maureen Ohlhausen on Sunday obtained by Business Insider, Yelp urged the FTC to reopen the investigation, arguing that an hourlong investigation yielded 385,888 images of local businesses posted by Yelp users that appeared in Google's local search results, a direct violation of the settlement.

"Google should be held accountable and subject to remedies sufficient to ensure its anticompetitive conduct does not continue to harm competition and consumers," Yelp Vice President of Global Public Policy Luther Lowe wrote in the letter.

No "scraping" clause

Following the 2012 settlement, Google agreed to stop scraping sites like Yelp for images, which Yelp argued reduced competition.

But the Wall Street Journal noted that Yelp noticed its images had begun showing up in Google search results last month.

The letter, which was also shared with several members of congress and attorneys general in every US State, was the latest salvo in the ongoing battle between the search engine giant and the business review site.

Yelp was not satisfied by the Google settlement in 2012, saying that the settlement would stifle innovation, and encourage "anti-competitive behavior."

While Google has been hit hard by antitrust regulators in Europe over the past several years, concerns about the search engine's dominance in the tech ecosystem have only recently steeped steadily into American political discourse.

A debate within the Democratic party over whether to take a harder stance on Google's antitrust lobbying spilled into the open last week after it was revealed that a monopoly critic at the center-left New America foundation was cut loose after praising the European Union's decision in July to impose a $2.7 billion antitrust fine on Google.